1: 100 percent / n-butyllithium / tetrahydrofuran / 1.) -65 deg C, 1 h, 2.) 0 deg C, 2 h 2: 1.) n-buthyllithium, hexamethylphosphoric triamide / 1.) a) THF from -78 deg C to -40 deg C, 2 h, b) -40 deg C, 0.5 h, 2.) a) -78 deg C, 15 min, b) 0 deg C, 1 h View Scheme